1. Field of the Invention
The present invention relates to a liquid ejection head adapted to eject liquid such as ink through an ejection orifice as well as to a process for producing the liquid ejection head.
2. Description of the Related Art
Conventionally, a liquid ejection head used in a liquid ejection apparatus includes a recording element substrate in which an ejection orifice adapted to eject ink is formed, a support member adapted to hold and fix the recording element substrate, and an electrical wiring substrate provided with lead terminals connected to connection terminals of the recording element substrate.
A connecting portion between the connection terminals provided on the recording element substrate and the lead terminals extended from the electrical wiring substrate is sealed by being covered with a sealant to prevent faulty connections due to corrosion caused by ink and a broken wire caused by external forces. As a method for sealing the connecting portion, a method has been adapted which applies the sealant to tops of the lead terminals, causes the sealant to penetrate through between plural adjacent lead terminals, and thereby fills the sealant into bottom part of the lead terminals.
However, with this sealing method, it is difficult to fill the sealant into a space in the bottom part of the lead terminals by a single sealant application operation, and cavities or bubbles will be produced in the bottom part of the lead terminals, which can lead to seal failure. This makes it necessary to fill the sealant into bottom part of the lead terminals by dividing the sealant application operation into a few parts.
Thus, as a measure to deal with the seal failure described above, Japanese Patent Application Laid-Open No. 2002-079675 discloses a configuration in which a sealant catcher is provided in the bottom part of lead terminals. This configuration allows the sealant catcher to catch the sealant penetrating through gaps between plural adjacent lead terminals toward the bottom part of the lead terminals, ensures covering ability of the sealant near the lead terminals, and enables preventing faulty connections due to corrosion caused by ink or the like.
With the configuration described in Japanese Patent Application Laid-Open No. 2002-079675, in which the sealant catcher is provided in the bottom part of the lead terminals, although sealing is provided near the bottom part of the lead terminals, cavities or bubbles could be produced between the recording element substrate and sealant catcher.
When cavities or bubbles are produced between the recording element substrate and sealant catcher, in a production process before hardening the sealant, the bubbles might move to near the lead terminals due to vibrations produced when the liquid ejection head is conveyed. Also, when the liquid ejection head is put into a high-temperature environment to harden the sealant, the bubbles might expand and come close to the lead terminals, creating a danger that the bubbles will explode to damage the connecting portion.
Therefore, if the liquid ejection head needs to be conveyed before the sealant hardens, it is necessary to pay close attention to the vibrations transmitted to the liquid ejection head. Also, it is necessary to conduct visual inspection and the like to control bubble expansion during curing.